Subsurface well apparatus with packing structures



Nov. 5, 1963 T. J. CARTER 3,

SUBSURFACE WELL APPARATUS WITH PACKING STRUCTURES Filed April 30, 1962 2 Sheets-Sheet 1 Iva/was (Z 6 7275)? INVENTOR.

flrraeusys.

NOV. 5, 1963 T. J. CARTER 3,109,493

SUBSURFACE WELL APPARATUS WITH PACKING STRUCTURES Filed. April 30, 1962 2 Sheets-Sheet 2 F1 6. FI/GO 71/0/1405 I]: 60275 INVENTOR.

Unite The present invention relates to subsurface well tools, and more particularly to well packers adapted to be set in packed-off condition in casings, liners, and similar conduit strings disposed in Well bores.

Some types of well packers embody an initially retracted pliant, elastic packing structure, to which endwise compressive force is applied for the purpose of effecting its shortening and expansion against the wall of an encompassing well casing, as well as its sealing against the periphery of the well pack-er body. In lowerleg such a well packer through fluid in the well casing, the pressure developed in the fluid has sometimes resulted in its being forced under the packing structure, hydraulically expanding the latter outwardly against the casing, and thereby producing an undesirable swabbing effect that causes difii-culty in running the packer to its setting depth, and which may also result in damage to the packer parts.

After the packing structure has been expanded against the well casing, fluid pressures imposed upon either of its end portions subject it to endwise compression, which should maintain its sealing effectiveness against the well casing. Such sealing occurs under high fluid pressure operating conditions, but the endwise compression resulting from low fluid pressures may be insufllcient to maintain the seal. against the well casing, fluid passing between the exterior of the packing structure and the well casing and esulting in low pressure leaks. In an attempt to prevent such low pressure leaks, the packing structure has been expanded by subjecting it to greater endwise compressive expansion force, but leaks still develop, apparently resulting from the fact that the unit pressure or" the end portions of the pliant, elastic packing structure was still at too low a value.

Accordingly, an object of the present invention is to provide a well packer embodying a pliant, elastic packing structure to which a greater unit end pressure is applied for the same total endwise compressive force to maintain the packing structure sealed off against the surrounding well casing, as well as increasing its sealing eiiectiveucss against the packer body on which the packing structure is mounted.

Another object of the invention is to provide a well packer embodying a pliant, elastic packing structure mounted on a packer body, in which fluid pressure in the well casing is prevented from passing into the packing structure so to expand it outwardly, as during lowering of the well packer in the well casing.

A further object of the invention is to provide a well packer embodying a pliant, elastic packing structure and an extrusion preventing device at an end portion of the packing, in which expansion of the extrusion preventing device against the surrounding well casing is accomplished in a more efficient and effective manner.

An additional object of the invention is to provide a well packer embodying a pliant, elastic packing structure adapted to be expanded against a surrounding well casing, in which more energy is stored in the pliant, elastic material of the packing structure as the result of its endwise compressive and outward expansion, thereby insuring its retention in a sealed-ft" state against the well casing and the packer body despite subsequent partial relief of the endwise compressive force imposed thereon.

States Patent 0 Patented Nov, 5,

2 Not only is more energy stored in the pliant, elastic material, but the latter is in its packedoi'l state at a higher unit pressure in the material.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which it may be embodied. Such forms are shown in the draw ings accompanying and forming part of the present specification. These forms will now be described in detail for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to Lhe drawings:

FIGURE 1 is a combined longitudinal section and side elevational view of a well packer disposed in a well casing, with the packer parts in their initial retracted positions;

PEG. 2 is a view similar to FIG. 1 disclosing the well packer after it has been anchored in packed-off condition in the well casing;

FIG. 3 is an enlarged longitudinal fragmentary section through a portion of the apparatus, with. its packing structure in retracted position;

MG. 4 is a view similar to PEG. 3 disclosing the packing structure portion of the apparatus in a partially expanded condition with respect to a surrounding well casing;

MG. 5 is a View similar to FIG. 3 disclosing the packing structure fully packed-off against the wall of the well casing;

FIG. 6 is a plan view, with a portion broken away, through the extrusion preventing ring elements embodied in the well packer;

FIG. 7 is an enlarged view of a modified form of pressure booster and expander ring forming part of the well packer;

PEG. 8 is a longitudinal section through an end portion of a modified form of pliant, elastic packing sleeve embodied in the well packer;

FIG. 9 is a view similar to FIG. 8 of yet another modified end portion of the packing sleeve;

FIG. 10 is a longitudinal section, similar to FIG. 3, through another embodiment of the invention.

The well packer A disclosed in FIGS. 1 and 2 is shown in detail merely for purposes of illustrating an organization in which the invention is embodied. The invention may be incorporated in many different specific well packem, where it is desired to maintain a proper leakproof seal against the wall of a surrounding well casing B, or against the periphery of a body it), or the like, on which the packing structure ll is mounted.

As shown, the specific well packer A includes the body ltl suitably secured to a running-in string C, such as a tubular string, extending to the top of the well bore and by means of which the packer is lowered to its setting location within the encompassing well casing B. The body carries a set of upper segmental slips 12 adapted to be moved into engagement with the casing by an upper frusto-conical expander 13 retained initially in retracted position by one or more shear screws 14 securing it to the body. The upper slips 12 are also retained initially in retracted position by shear screws 15 securing them to the expander 13 and the body all. A lower set of segmental slips 16 is held initially in retracted position above and adjacent to a body guide Fl by being attached to the main body it) through the medium of shear screws lid and to a lower trusts-conical expander 19 through additional shear screws 2%, the latter expander being held initially in ineifective position by suitable frangible. con- 3 nections in the form of shear screws 21 threaded into the body.

The packing structure 1 1 is mounted on the body 1d between the upper and lower expanders or abutments 13, 19, and includes a packing sleeve 22 of pliant, elastic material, such as synthetic or natural rubber. The normal or initial retracted condition of the packing sleeve 22 is such that its outside diameter conforms substantially to the outside diameters of the upper and lower expanders or abutments 13, 1%, which have a substantial running clearance with the well casing 33. By relatively shifting the expanders 13, '19 toward each other, the packing sleeve 22 is subjected to endwise compression, which shortens it and effects its. outward expansion against the wall of the well casing, as well as forcing it inwardly against the periphery of the body 10.

A setting sleeve 23 is disposed above the upper slips 12 and is slidable relatively downwardly along the body of the tool in efifecting expansion of the slips 12, 16 and packing structure 22 against the well casing. This setting sleeve carries a split lock ring 24 having internal ratchet teeth 25 adapted to mesh with companion external ratchet teeth 26 on the body facing in a downward direction. Coengaging cam surfaces 2'7, 23 on the setting sleeve and the lock ring tend to urge the lock ring 24 into full mesh with the body ratchet teeth 26, in the event the body tends to move downwardly with respect to the setting sleeve 23, or the setting sleeve tends to move upwardly relative to the body. The slips 12, 16 and packing structure 11 are expanded outwardly as the result of relative downward movement of the setting sleeve 23 along the packer body It? or relative upward movement of the packer body along the sleeve, or a combination of these two movements.

The well packer A is run in the well casing to the desired setting point, whereupon a downward force is imposed on the setting sleeve 23 by any suitable means, the setting sleeve engaging the upper slips l2 and shearing the screws attaching them to the packer body and to the upper expander, sliding the upper segmental slips :12 downwardly along the upper expander 13 and outwardly against the wall of the well casing B. The running-in string C and body 10 are then shifted upwardly, which will shorten the packing sleeve structure 11 by shearing the screws 14 holding the upper expander 13 to the body 10 and by moving the lower expander 19 toward the upper expander, expanding the packing sleeve 22 against the casing wall and the exterior of the main body. A continuation of the upwardly directed strain on the tubing string C and body it) will shear the screws 18, Zil, 21 holding the lower slips 16 to the body 16 and expander 1?, and the expander 19 to the body, causing the guide 17 at the lower end of the body to engage the lower slips 16 and move them longitudinally along the outer tapered face of the lower expander 19 and radially into engagement with the casing. An increase in the upward strain will further move the lower slips 16 and expander 19 toward the upper slips 1 2 and expander 13, further compressing the packing sleeve 22 between the casing wall and the exterior of the body 1t} to effect a leakproof seal therebetween.

The parts are retained in the set position illustrated in FIG. 2 by preventing downward movement of the body 10 relative to the parts surrounding it. This is accomplished by the engagement of the body ratchet teeth 26 with the lock ring teeth and by the interaction of the cam surfaces 27, 23, the downward :force being transmitted through the ring to the sleeve 23 and from the latter through the upper slips 12, upper expander 13, packing structure 11, lower expander 19 to lower slips 16, which are embedded in the wall of the well casing B and which will, therefore, preclude downward movement of the well packer. Upwardly directed force on the packer body 10 will be transmitted through the guide 17, lower slips 16, lower expander 19, packing structure 11, upper expander 13 and slips 12 to the well casing. Thus, the well packer .4 A is anchored against movement in both longitudinal directions in the well casing B.

The upper and lower expanders 1d, 19 form abutments at the upper and lower ends, respectively, of the pliant, elastic packing element or sleeve 22. The end portions 30 of the packing sleeve are reduced in external diameter, providing recesses fill in each of which a pressure booster and expander ring 32 is disposed. This ring is rigid and circumferentially continuous, its inner surface 33 snugly embracing the periphery 34 of the end portion Bil, pressing the latter against the periphery 35 of the packer body 19. Its outer diameter conforms to the outside diameter of the retracted packing sleeve 22 and of the adjacent abutment 13. The outer corner 36 of each solid, rigid pressure booster and expander ring 32 is beveled, being inclined inwardly toward an adjacent abutment or expander 13, the lower outer portion 37 of which is also beveled or inclined in an inward direction toward the end portion 30 of the packing sleeve 22. The beveled pressure booster and expander ring 32 and opposed abutment 13 form a generally triangular space in which a cold flowing or extrusion preventing device 38 is mounted, this device being disposed initially in a retracted position, but being expandable outwardly against the wall of the well casing B to bridge the gap or clearance space 39a between the abutment 13 and easing wall through which the pliant, elastic material of the packing sleeve 22 might otherwise be extruded or squeezed as the result of high pressure or high temperature conditions encountered in the well bore, or in the presence of a combination of both conditions.

The extrusion preventing device 38 per se forms no part of the present invention, being described and claimed in US. Patent 2,896,724. One of these devices is provided between each end portion 36 of the packing sleeve and an adjacent abutment 13 or 19. The description of one will suffice for both, since the packing structure adjacent to the upper abutment 13 is the same as the packing structure adjacent to the lower abutment 19, although reversely arranged.

The extrusion preventing device 33 includes an outer metallic split ring 39 having an inner tapered surface 49 engageable with and companion to the tapered surface 37 on the abutment 13, the ring being of generally right triangular cross-section, its outer surface 41 being genrally cylindrical and its lower surface 4-2 relatively fiat and substantially normal to the axis of the well packer. An inner ring 43 is reversely arranged to the outer ring, having a tapered inner surface 44 engageable with and companion to the tapered surface as on the pressure booster and expander ring 32. This inner ring is also of generally right triangular cross-section, with its outer surface 45 generally cylindrical and forming a continuation of the outer surface 41 of the other ring 39 and with its upper surface 4-6 also normal to the axis of the well packer and abutting the lower surface 42 of the outer ring. The inner and outer rings 43, .39 substantially fill the generally triangular gap or groove defined by the tapered surface 37 on the upper abutment 13 and the confronting inclined surface 36 on the solid booster and expander ring 32.

The extrusion preventing rings are each split (FIG. 6) and normally tend to remain in a retracted position, such as disclosed in FIGS. 1 and 3. The splits 48, 49 of the rings are staggered with respect to each other and may preferably be displaced approximately 186 degrees from one another. These rings 39, 4 3 are expandable outwardly to bring their outer cylindrical surfaces 41, 45 into engagement with the cylindrical wall of the well casing B.

To assure the same extent of outward expansion of the extrusion preventing rings 39, 43, they are keyed to one another for circumferential sliding movement with respect to one another, relative radial movement therebetween being prevented, all by an arcuate key and slot arrangement. As specifically disclosed, one of the rings 4-3 has a circumferential rib 5t} projecting upwardly from its sac-aces upper face and fitting within a companion circumferential groove 51 in the lower portion of the other ring 3 By virtue of the key and keyway or slot arrangement 51, Ell, the rings 39, 43 will expand outwardly to the same extent, as described hereinbelow. However, the interconnection 5d, fill between the rings will not prevent such expansion from occurring.

As stated above, the upper and lower portions of the packing structure are the same, being oppositely arranged, so that a description of the lower portion is deemed to be unnecessary.

In assembling the packing structure 3,1 on the well packer, the packing sleeve 22 is slipped over the upper end of the body lltl, as well as each pressure booster and expander ring 32. The inside diameter of each of these latter rings is preferably slightly less than the normal outside diameter 34 of an end portion Bil of the packing sleeve, so that the ring 32 must be forced over the end portion 3t and will press the inner surface of the end portion firmly against the periphery S5 of the packer body, preventing fluid leakage therebetween. Such lluid eakage would otherwise occur, as during lowering of the well packer through the fluid in the well here, the pres sure [developed in the well bore fluid, as the result of running the well packer therewithin, passing between the packing sleeve 22 and the packer body lid and tending to inflate the packing sleeve outwardly toward and against the well casing, the packing sleeve then functioning as a swab in the well casing, which. is not desired.

The inward pressure of the ring 32 against the end portion 3% of the packing sleeve can be enhanced, as by providing a circumierentially continuous head 55 on the inner portion of each ring 32a, as disclosed in FIG. 7. When forced over an end portion fit"? of the packing sleeve, this bead will compress the end portion inwardly against the body, and due to the concentrated area over which the bead 55 is acting against the end portion, such end portion has a greater unit pressure imposed thereon and will engage the periphery of the body at a higher unit pressure, particularly in the region opposite the location of the circumferential bead In lieu of providing a bead 515 that extends inwardly from the booster and expander ring 32a, the end portion 30:! of the packing sleeve may have a circumferentially continuous head 56 mounted on its exterior surface and extending outwardly therefrom (FIG. 8). When the ring 32 is forced over the end portion 3%, it will exert an inward compressive force on this head 56, subjecting the end portion Ella of the packing sleeve to a relatively high unit pressure and forcing it against the periphery 35 of the packer body The same effect can be accomplished by forming the end portion 3% (FIG. 9) with an inwardly projecting circumferentially continuous bead 37 disposed opposite the booster and expander ring 32. T his booster and expander ring 32 when forced over the end portion Iiitb of the pack ing sleeve, will transmit its compressive force to the end portion 3% upon the head 57. Since the latter has a relatively small area, the inward compressive force is concentrated over a small area of pliant, elastic material, resulting in a high unit pressure of the head 57 being exerted against the periphery 355 of the packer body ill, there-by preventing leakage of fluid between the end portion 3%!) and the packer body during lowering of the well packer in the well casing, or, for that matter, during elevation of the well packer through the fluid therewithiu.

The packing structure ii is assembled on the well packer, with the several parts in their relationship disclosed in FIGS. 1 and 3, in which the outer and inner split metallic extrusion preventing rings 4-3, 39 are in retracted position, as well as the pliant, elastic packing sleeve As set forth above, the apparatus A is run through the fluid in the well casing to the desired setting point, after which the upper slips 12 are tripped and expanded outwardly, followed by shortening and expansion of the packing structure 11 into engagement with the wall of the well casing, and the setting of the lower slips it against the wall of the Well casing. During the shortening of the packing structure llll, each solid non-expandable pressure booster and expander ring 32 is exerting an axial thrust upon the inner extrusion preventing ring 43, an axial thrust also being exerted between the opposed abutment 11% and the outer split metallic extrusion preventing ring 39. As a result, both the booster and expander ring 37; and the abutment 13 act upon the inclined faces 54, ill of the extrusion preventing rings and urge them in an outward direction toward the wall of the well casing B, an intermediate position of outward expansion being disclosed in FIG. 4, in which the packing sleeve 22 has been expanded out against the wall of the well casing, but in which the extent of compressive force tending to shorten the packing sleeve 22- has not reached its maximum value.

Even with such incomplete packing oil of the packing sleeve 22 against the wall of the well casing B, as well as against the periphery 35 of the packer body 10, the end region '6 of the packing 22 has a higher unit pres sure in its material, ten-ding to urge it against the well casing and also against the periphery of the body. Since the total compressive force imposed on the end region so of the packing is being transmitted essentially through the pressure booster and expander ring 32, which is acting on the packing sleeve over the comparatively small area R indicated in the drawings, the packing sleeve, being of a fluid-like material, will transmit this relatively high unit pressure through the adjacent region of the packing sleeve and urge the latter at a relatively high unit pressure against tle casing wall and against the periphery of the body At this time, the engagement of the abutment 3 with the terminus all or" the end portion 3a of the packing sleeve, such as shown in FIG. 4, will not impose much of a force on the end portion of the packing sleeve, since the unit pressure at the terminus is dissipated, to some extent, by the fact of the rubber material flowing upwardly into the gap as that exists between the inclined face 37 of the abutment and the inclined face 4 d of the packing extrusion ring 43, the space also being defined, as shown in the drawings, by an inner beveled face o3 at the inner, upper corner or" the booster and expander ring 32.

As the endwise compressive force on the packing struc ture ill increases, the abutment l3 and the solid non-expandabie circumferentially continuous ring 32 coact to shift the extrusion rings outwardly into full surfiace engagement with the wall of the well casing B, to bridge the clearance space or gap 3% between the abutment l3 and the \wall of the well casing (FIG. 5). At this time, the endwise compressive force is predominantly being transmitted through the booster and expander ring 32 to the end region dil of the packing sleeve 21% over the comparatively small area R, which is substantially less than the full expanded cross-sectional area S of the packing sleeve, resulting in a very high unit pressure being imposed on the packing sleeve in the region 61) of the booster ring, which unit pressure is transmitted in all directions, as in a liquid, to hold the packing sleeve sealed off at a high unit pressure against the wall of the well casing B, as well as against the periphery of the packer body ltl.

Some of the endwise compressive force will be transmitted directly from the abutment 3 to the terminus at of the packing sleeve, such as shown in PKG. 5, but in view of the design and relationship of the parts, the booster and expander ring 32 does not contact the abutment 13. A gap as remains between the ring IE2 and abutment 13 into which packing material can pass, which tends to minimize the unit pressure at the endmost portion 61 of the packing sleeve.

As the packing material is deformed, it flows around the exterior or the booster and expander ring 32 (FIG. 5) and into enga ement with the extrusion preventing ring 43. The compressive force imposed on the packing sleeve 22 will be transmitted over a greater area, namely, the area of the booster and expander ring 32 and some of the area of the extrusion preventing ring 43 and the innermost portion of the abutment 13. However, the main concentration of the force Will still be through the relatively small cross-sectional area R of the booster andexpander ring 32, resulting in the maintenance of a high unit pressure in the end regions as of the packing sleeve, urging it into leakproof contact with the Wall of the W611 casing B and with the periphery of the body lib.

It is to be noted that the packing sleeve 22 itself does not materially contact the extrusion preventing device 3? in effecting its expansion, as in prior devices, such as the above referred to US. Patent 2,896,724. It is the pressure booster and expander ring 32 which contacts the expansible extrusion preventing device 38 and urges it outwardly toward and into engagement with the wall of the well casing B. As disclosed in the above patent, the packing sleeve 22 contacts the extrusion preventing device itself, as well as the adjacent abutment 13, so that the endwise compressive force imposed on the packing sleeve is transmitted throughout its entire cross-sectional area, designated S in the drawings of the present application. Accordingly, the rubber pressure is at a much lesser unit value than in applicants device, and there is a greater tendency for leaking around the exterior of the packing element 22, as Well as between its interior and the periphery 35 of the body 10.

Because of the concentration of the endwise compressive force through the area R of the booster and expanderring, the packing material in the regions of its ends 63 is at the higher unit pressure, so that the subjecting of a packing 22 in the condition illustrated in FIG. 2 to relatively low pressures, either imposed from below the well packer or above the well packer, does not result in leaking past the periphery of the packing sleeve, as in prior devices. The greater the hydraulic pressure, the g eater is the compression on the packing sleeve 22 produced by such pressure. However, under low pressure conditions, the packing sleeve may not be urged by such pressure with sufficient force against the wall of the well casing, producing the aforenoted low pressure leaking condition. With applicants device, even with such lesser hydraulic endwise force imposed on the packing element, leaks do not occur since the relatively low total compressive force is concentrated over a smaller area R and will result in the packing material adjacent to the booster and expander ring 32 being at high unit pressure, the same unit pressure being exerted by the pliant, elastic packing material against the wall of the well casing 13 and the periphery of the packer body.

As the endwise compression on the packing sleeve increases, either as a result of a mechanical shifting of the abutments 13, 19 relatively toward each other, or as a result of hydraulic pressure, the extrusion preventing rings 38, if they have not been expanded fully against the wall of the well casing, will be so expanded, the expansion occurring as the result of the contact of the booster and expander ring 32 therewith. The use of the ring 32 as an expander for the extrusion preventing rings results in a more efiicient and effective expansion than occurs when the packing sleeve directly engages such rings, as in the above patent. Thus, assurance is had that there will be full outward expansion of the extrusion preventing rings 39, 43 against the Wall of the well casing to bridge the annular clearance space or gap 3% between the abutment 13 and the wall of the well casing B.

The use of the booster and expander ring 32 enables more energy to be imparted to the packing sleeve 22 in effecting its full packed-off condition against the wall of the well casing than in prior devices. It is to be noted that the external portion 762 of the packing sleeve is axially spaced from the extrusion preventing device 33 when the parts are in their retracted position, as disclosed in FIG. 3.

When the packing sleeve 22 is shortened and expanded against the wall of the well casing, it must thereafter flow around the exterior of the booster and expander ring 32 before coming into contact with the, anti-extrusion device 38, which will preclude the flowing of the packing material through the clearance space 3% between the abutment and easing wall. Accordingly, a greater compressive force is required to insure the contact of the material of the packing sleeve 22 with the anti-extrusion device 38 than when the packing sleeve 22 directly contacts the antiextrusion device 33, as in the above patent. Accordingly, a much greater amount of energy is transmitted to and stored in the packing sleeve 22 to maintain it in a fully packed-oh condition, and this greater energy stored in the pliant, elastic packing material has a higher unit pressure adjacent to each booster and expander ring 32. As a result, a very eificient seal is maintained against the casing wall and the periphery of the packer body.

In view of the much greater energy stored in the packing sleeve to secure a fully packed-otr" condition, such as disclosed in H6. 5, any tendency for the abutments 13, 19 to shift axially slightly away from each other, which might occur as the result of certain conditions in the well casing, will not result in leaking of the well packer. Some of the stored energy might be dissipated or relieved, but the necessity for initially imparting a greater amount of energy to the packing material, than heretofore, will result in a large amount of stored energy still being available to insure an efi'lcient and effective pack-on? of the sleeve 22 against the casing wall and periphery of the body 10.

The form of invention illustrated in FIG. 10 is essentially the same as that previously described. The pressure booster and expander ring 320 is provided with an inwardly directed flange 8d slidable upon the periphery of the packer body 10, to insure the appropriate centering of the ring 32c relative to the body axis. The skirt portion 81 of the ring is pressed upon the end portion 30d of the packing sleeve, as in the other form of the device, to force the inner surface of the end portion against the periphery of the body of the tool. However, the end portion 30d of the packing is made much shorter than in the other forms of the invention, and terminates a substantial distance from the inwardly directed flange 89. Accordingly, when the packing structure is to be expanded against the wall of the well casing, the total endwise compressive force upon the packing sleeve will still be concentrated over the relatively small area R or" the skirt portion 81 of the ring, thereby producing higher unit pressure in the packing sleeve in the region of the booster and expander ring 320. The terminus 61a of the end portion 30d will not engage the inwardly directed flange 3% as the result of the outward expansion of the packing sleeve 22 against the wall of the well casing B.

I claim:

1. A packing structure, including an initially retracted pliant, elastic packing member adapted to be expanded outwardly into engagement with a companion wall, an abutment adjacent to an end portion of said member, an expandable device engaging said abutment, and a rigid, circumierentially continuous pressure booster and expander member engaging said expandable device and also engaging said packing member over substantially less than its full cross-sectional area when said packing member is initially retracted to expand said device against the companion wall upon expansion of said packing member against the companion wall.

2. A packing structure, including an initially retracted pliant, elastic packing sleeve adapted to be expanded outwardly into engagement with a companion wall, an abutment adjacent to an end portion of said sleeve, an expandable device engaging said abutment, and a rigid, ci-rcu mferentially continuous pressure booster and expander member engaging said expandable device and also engaging said packing sleeve over an end area extending inwardly from the outer periphery of said packing sleeve and terminating substantially short of its inner periphery to expand said device against the companion wall.

3. A packing structure, including an initially retracted pliant, elastic packing member adapted to be expanded outwardly into engagement with a companion wall and having an end portion of substantially less outside diameter than the outside diameter of the main portion of said packing member, an abutment adjacent to said end portion, an expandable device engaging said abutment, and a rigid, circumferentially continuous pressure booster and expander member encompassing said end portion and engaging said expandable device and also axially engaging said packing member only over an end area extending laterally outwardly from said end portion to expand said device against said companion wall.

4. in a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diameter of the main portion of said packing member; an abutment on said body adjacent to said end portion; an expandable device engaging said abutment; and a rigid, circumferentially continuous pressure booster and expander member engaging said device to expand it against the casing and embracing said end portion to force said end portion inwardly against the periphery of said body, said expander member axially engaging said packing member only over an end area extending laterally outwardly from said end portion.

5. in a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diamctcr of the main portion of said packing member; an abutment on said body adjacent to said end portion; an expandable dcvice engaging said abutment; and a rigid, circumfercntially continuous pressure booster and expandcr member engaging said device to expand it against the casing and embracing said end portion to force said end portion inwardly against the periphery of said body, said expander member axially engaging said packing member only over an end area extending laterally outwardly from said end portion, one of said expander member and end portion having a circumferential side rib to increase the inwardly directed force of said end portion against said body with said expander member embracing said end portion.

6. In a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diameter of the main portion of said packing member; an abutment on said body adjacent to said end portion; an expandable device engaging said abutment; and a rigid, circumferentially continuous pressure booster and expander momber engaging said device to expand it against the casing and embracing said end portion to force said end portion inwardly against the periphery of said body, said expander member axially engaging said packing member only over an end area extending l-aternlly outwardly from said end portion, said expander member having an inner circumferential rib bearing against said end portion to increase the inwardly directed force of said end portion against.

said body.

7. In a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diameter of the main portion of said packing member; an abutment on said body adjacent to said end portion; an expandable device engaging said abutment; and a rigid, circumfcrentially continuous pressure booster and expander member engaging said device to expand it against the casing and embracing said end portion to force said end portion inwardly against the periphery of said body, said expander member axially engaging said packing member only over an end area extending laterally outwardly from said end portion, said end portion having an external circumferential rib embraced by said expander member to increase the inwardly directed force of said end portion against said body.

8. In a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diameter of the main portion of said packing member; an abutment on said body adjacent to said end portion; an expandablc device engaging said abutment; and a rigid, circumfercntially continuous pressure booster and expander member engaging said device to expand it against the casing and embracing said end portion to force said end portion inwardly against the periphery of said body, said expander member axially engaging said packing member only over an end area extending laterally outwardly from said end portion, said end portion having an internal circumferential rib bearing against said body to increase the inwardly directed force of said portion against said body with said expander member embracing said end portion.

9. In a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to be expanded against the well casing and having an end portion engaging said body of substantially less outside diameter than the outside diameter of the main portion of said packing member to provide an end shoulder laterally outwardly of said end portion; an abutment on said body adjacent to said end portion; an expandable device engaging said abutment; and a rigid, circumfcrcntially continuous pressure booster and expander member having a tapered surface engaging said expandable device to expand it against the casing and embracing said end portion to 'force said end portion in wardly against the periphery of said body, said expander member axially engaging said shoulder and being free from axial engagement with said end portion.

10. A packing structure, including an initially retracted pliant, elastic packing member adapted to be expanded outwardly into engagement with a. companion wall and having an end portion of substantially less outside diameter than the outside diameter of the main portion of said packing member to provide an end shoulder laterally outwardly of said end portion, an abutment adjacent to said end portion, an expandable device engaging said abutment, and it rigid, circumferentially continuous pressure booster and expander member encompassing said end portion and having a tapered surface engaging said expandable device to expand it against the companion wall, said expander member axially engaging said shoulder and being free from axial engagement with said end portion.

11. In a well packer to be set in a well casing: a body; an initially retracted pliant, elastic packing member on said body adapted to'be expanded against the well casing and having an end portion engaging said body of sub stantinlly less outside diameter than the outside diameter of the main portion of said packing member to provide an end shoulder laterally outwardly of said end portion; an abutment on said body adjacent to said end portion; an expandable device engaging said abutment; and a rigid, circumfcrentlally continuous pressure booster and expander member having a tapered surface engaging'said expandable device to expand it against the casing and embracingsaid end portion to force said end portion inwardly againstthe periphery of said'body, said expander member axially engaging said shoulder and being free from axial engagement with said end portion, said expander member having a flange extending inwardly to said body and being free from engagement with said end portion.

12. A packing structure, including an initially retracted pliant, elastic packing member adapted to be expanded outwardly into engagement with a companion wall and having an end portion of substantially less outside diameter than the outside diameter of the main portion of said packing member to provide an end shoulder laterally outwardly of said end portion, an abutment adjacent to said end portion, an expandable device engaging said abutment, and a rigid, circumferentially continuous pressure booster and expander member encompassing said end portion and having a tapered surface engaging said expandable device to expand it against the companion wall, said expander member axially engaging said shoulder and being free from axial engagement with said end portion, said expander member having a flange extending inwardly across said end portion and being free from engagement 19 with said end portion.

No references cited. 

1. A PACKING STRUCTURE, INCLUDING AN INITIALLY RETRACTED PLIANT, ELASTIC PACKING MEMBER ADAPTED TO BE EXPANDED OUTWARDLY INTO ENGAGEMENT WITH A COMPANION WALL, AN ABUTMENT ADJACENT TO AN END PORTION OF SAID MEMBER, AN EXPANDABLE DEVICE ENGAGING SAID ABUTMENT, AND A RIGID, CIRCUMFERENTIALLY CONTINUOUS PRESSURE BOOSTER AND EXPANDER MEMBER ENGAGING SAID EXPANDABLE DEVICE AND ALSO ENGAGING SAID PACKING MEMBER OVER SUBSTANTIALLY LESS THAN ITS FULL CROSS-SECTIONAL AREA WHEN SAID PACKING MEMBER IS INITIALLY RETRACTED TO EXPAND SAID DEVICE AGAINST THE COMPANION WALL UPON EXPANSION OF SAID PACKING MEMBER AGAINST THE COMPANION WALL. 